Campbell Hausfeld air compressors are available from a number of sources and this company is a key manufacturer / supplier of private labeled air compressors for a host of other companies as well.
If we could assign a pedigree to a company, then Campbell Hausfeld air compressors certainly have it. The company has been around since 1863. Currently the Campbell Hausfeld is owned by Marmon Holdings, themselves part of the Berkshire Hathaway group.
Many folks consider Campbell Hausfeld air compressors to be low end, low cost, small workshop or garage shop oriented. This is true. They are that. Yet they are more.
A visit to their website shows that they offer a commercial line of air compressors as well. Unfortunately, when you click the link to their commercial site there is no content on the page. Some of the drop down menus work on the commercial site, but my goodness, such a poor website is more than a bit strange for a company of this size and history. This is the situation in early 2016, at least.
In any case, their commercial line of compressors are both rotary screw and reciprocating, with 5HP motor size and up. The commercial line of Campbell Hausfeld air compressors is available from outlets such as Acklands Grainger, Grainger, Northern Tool, Global Industrial and others.
As to the Campbell Hausfeld smaller air compressor market, they offer quite a range.
From small, fractional HP compressors, to portable units from 1 HP and up, Campbell Hausfeld offer a broad range of DIY air compressors. They can be purchased in many big box stores, and at a host of on line sales sites including Amazon.
One of the good things about Campbell Hausfeld is, if you can locate your air compressor model number, you can usually download the manual and operating instructions for that model from their site. That is a huge plus if you are looking for CH info. Visit the site here: http://www.campbellhausfeld.com/, and drill down to the various pages to find lots of info.
Campbell Hausfeld is a key supplier of privately branded air compressors. If you acquire a different brand and you are looking for information about that brand, check out the models on the CH website. You may find that your different brand air compressor is identical (except for the color) to a CH product, and, if so, typically parts from the Campbell Hausfeld compressor will fit on the other brand.
If you are unable to get help or information about your Campbell Hausfeld air compressor, feel free to use this forum page we have set up. Of course, only questions and comments about the Campbell Hausfeld line of air compressors can be posted here.
Hello: I have a Campbell Hausfeld portable compressor, 3 gallon tank, no oil. It has been working ok, but now smells like electrical burning (increasingly stronger odour each time it comes on) although I can’t find anywhere around the tank or the box that sits on top where it feels hot. I’m using it with an Arrow stapler to do some upholstery work. Any ideas?
Sure Lise. Run it for a while, unplug, dump all air, pull the cover off, and check the temp of the motor and / or motor capacitor if there is one. Let us know what’s what, will you?
Hi. I am having a difficult time finding any manuals for my CH 20Gal horizontal compressor. Model # VT610302. It is one I received from my old work place and I’d like to service it and keep it working.
Thank you for any help.
Regards,
David
Assuming you haven’t already done so, please see this link for the info on a 6104. It is possible the pump and accessories are the same as yours, and if so, contact them at the contact info shown and ask about your 6103. If you’ve already been down this path David, indicate so, and then we’ll throw ourselves on the mercy of the visitors to ask if anyone has a digital copy of the 6103 manual for you.
Hi, of course I found this site AFTER buying a compressor. This is my first compressor, picked up a Campbell Hausfeld model VS500601AJ. FYI, I cannot find any info online for that model number, but can find the VS500602…
I plan to use sporadically, weekend warrior. Thinking I’ll set up mainly stationary in garage for auto work, have remodel projects kicking off and will use nailer, etc. and sprinkler blow out.
I have the following questions.
1) Any idea difference between the …601 and …602 models?
2) Air was leaking from the top compression nut of discharge tube; tube was distorted, nut stuck, so replaced entire tube with 3/8″ (1/2″ OD) type L; is that OK?
3) Filled tank to ~120 psi and let sit over night; lost ~6 psi. Is this loss worth looking into or OK?
4) The air filter attachment, plastic cover is zip tied on. Any suggestions for replacing this with a better air filter?
5) Should I modify the drain cock at bottom, so it’s easier to access while stationary in garage?
Any other considerations I’m not thinkin of? Adding pics hopefully to help…
Thanks,
Kieran
pics.
A 6 PSI drop overnight probably means a small leak in the tank check valve. Fix or not is up to you. If it gets bigger… maybe then.
As to the intake filter, remove the housing from the intake port, measure the intake port, and find any make that has the same size male thread and same intake hole / screen / mesh size and I expect it will work just fine. Probably not a good idea to run without one for sure, and the elements do need clean or replacing from time to time depending on the run time of that compressor.
Hi, I have a Campbell Hausfield hj300101. When turned on, it reaches about 40 psi and shuts off. Will not restart auto or manually till tank empty. Replaced switch, same thing. Help!
Shuts off or reset trips off? Sounds like it might be overheating. Try again, when it shuts off, let it cool by itself, don’t turn the pressure switch off, and see if it tries to restart when cold. If so, something is causing the motor to heat up. Could be a mechanical bind issue, but my thoughts are it could be the run capacitor getting weak.
I have a 15 or so year old 7.5 hp 80gal Campbell Hausfeld. It’s a two stage and I just moved it from my work shop to personal garage and it won’t start up. When I direct wire it to the fuse box and flip the fuse it just will just buzz/hum. The fan turns free and it was running no problems before moving. There is also no visible sign the capacitors are bad. I’ve gone through all the steps and I’m still stumped! Any ideas would be greatly appreciated.
Is the amperage of the power source fuse / breaker the same as it was? If so, please actually check the caps, as the symptoms sure suggest that this is the issue.
It’s a two stage; I’ll Look for a valve somewhere in the line between the first and second stages, or maybe in the head of the first stage. Thanks so much for your quick and useful responses.
Sure. Keep us posted if you will. Good luck.
I have a Campbell Hausfeld compressor model number HS050000AV with an 80 gallon tank and a 5hp 240v motor. It’s 12 years old and has 328 hours on it. I replaced the motor at 301 hours. It’s run well all these years and gets regular maintenance. The problem I’m having is while running normally it often bogs way down till you can almost count the pump cycles, then the belt develops a screeching noise, and eventually (10-20 seconds) it will go back up to normal rpm. Then a minute or 2 later, it repeats. To me it sounds like that can’t be good for the motor, but I can’t figure out what the problem is. Any ideas greatly appreciated!
No, I suspect too it cannot be good for the motor.
It sounds as though there is back pressure building up, the increasing load is slowing the pump – the motor wants to continue rotating at the normal speed – and that could lead to belt screech.
I’m leaning towards a valve in the pump, or in the lines that go to the tank being compromised in some way and that is leading to back pressure. After the compressor slows, there is time for the back-pressure to bleed off, and the motor and pump continues at normal speed.
Those are good thoughts. Thank you. I can’t imagine the line that goes from the second stage pump to the tank could be compromised; can it get clogged somehow from pump air output? What valves are present in the pump that could cause this? Are they replaceable? Could it be related to the pressure switch at all? Thanks!
Tim, I don’t have the pump in front of me to examine. Is it a two stage or just dual piston? If two stage, then there’s a line between first stage and second, and that second has in intake valve. Follow the air. There’s got to be a tank check valve, which may be the issue, or, more likely, it’s the valve(s) in the pump head.
I have a CH compressor WL60001AJ that needs a new pressure switch. The compressor was donated to me, and the on/off lever is missing, and I really don’t know if the rest of the switch is broken or not. The parts sellers say the switch is no longer available. So what can I do? the original switch is W207589AV. Thanks.
Please add a comment here with a photo of your compressor and a closer photo of the existing pressure switch. Thanks.
Pics added. The compressor is also missing the upper shroud (NLA), and 3 of the 4 fan blades on the motor shaft are broken off, so would need to replace that as well.
The compressor runs and builds pressure. Apparently the pressure switch is stuck in the “on” position as it begins running when I plug it in. I haven’t figured out exactly how the switch operates, I am not seeing how the switch mechanism opens the contact points.
I stumbled across someone who 3D printed a new on/off lever, but as I mentioned, not sure if that is the only issue with this pressure switch.
If I am able to repair the switch, I’m sure I will dismantle it and clean it up internally, as best I can.
But if some replacement switch were available at a reasonable cost, might be the way to go.
Also keeping an eye on ebay for the switch.
Thanks for the pics. On the 3rd pic I can see the specs for that switch, and also, that it’s mounted on a manifold. I am assuming that the manifold is, in turn, threaded onto the nipple sticking straight up out of the tank?
I just googled “95 – 120 PSI pressure switch on a base” and found a number that would be fine for this compressor. Just make sure that the one you buy is close to the same pressure range, no more than 5 PSI higher on the cut out, and that the voltage is 120/240. I believe almost all are now. Cheers.
Thank you for the information, apparently easier than I thought.
I’m thinking that instead of going with an all-in-one solution (the ones I saw on Amazon look pretty cheap, perhaps you could comment), perhaps a Square-D pressure switch (9013FHG12J52M1X), and pick up a regulator from possibly Harbor Freight, maybe one with an integrated water separator.Guess I shouldn’t complain about cheap, and in the next sentence promote HF, right?
Again I appreciate you setting me on a path to successful repair!
Square D offers excellent product, but I question the worth of using them here. A FURNAS or LEFOO brand would do the job nicely and in the fullness of time, would be a lower cost replacement than the Square D. As to the fan, if you measure the fan diameter, the shaft diameter, and Google replacement compressor fan, I’m sure you will find one that’s close enough to the original to replace it.
A regulator with a filter is an excellent idea. Many folks don’t use their compressors enough to make water a real problem. Just know that every time the compressor pumps air it’s also pumping water into the tank which is one reason why it’s important to drain the tank regularly. In terms of using HF stuff, I expect that almost all of the lower cost regulators, or filter regulators, are made in China, regardless of where they are acquired, so you may as well use the lowest cost source.
I have a cambel model wl 604003aj, it stars for a second and pops the breaker 20 amp, nothing else on it . not used to fixing these things what could it be?
Please go here and scroll down to, and read, the pages about air compressors that won’t start, for some things to check: https://fix-my-compressor.com/air-compressor-problems-and-fixes/
One of those things is the start capacitor, and my guess is that your compressor capacitor may be the issue. It needs testing. If you aren’t used to fixing things, this may be a bit beyond your skills right now. Know anyone local that can help? Good luck.
I have a Campbell Hausfeld WL611102AJ with a broken compression ring. Is there any way to replace it?
At one point you could buy a piston service kit, but apparently no longer.
If you have the ring, measure O.D., I.D., width and thickness and google “replacement compressor piston rings” and use the dimensions you’ve gathered to talk to the people that actually make them, of which there are many.
I have a 11 Gallon 3.5 HP combination. It is a 1996 Campbell Hausfeld WL600605AJ.
The regulator has been previously replaced, and I don’t see an unloader anywhere.
The check-valve has a plug in it where I would expect to see an unloader port.
The pump will start ok if I disconnect the tube from the pump to the tank, and it will continue to build pressure up to 125psi once I reconnect it (while the pump is running).
After this, it chugs to try to restart and will eventually blow a 20 amp breaker.
I have replaced both capacitors with no change.
This even happens if the tank is full but I temporarily disconnect the tube before trying to restart. It simply won’t restart when the tank has pressure (even if the tube does not).
The motor and pump both move easily when turned by hand.
At this point, I’m debating whether to try opening the motor to see if there is a bad connection to the start capacitor, or I can try to replace the pressure switch with one that has an unloader port and install a new check valve with port.
However, I don’t have a lot of hope for this, as even if I start it up with a loose connection (to allow some air to vent from the fill tube), it won’t start.
The parts description is here: http://parts.campbellhausfeld.com/IMAGES/pdfs/manual04/201805_0303.pdf
Any ideas?
I found I think, an image of the plumbing of the WL600605AJ. It clearly shows an unloader line (known as exhaust tube #4 in your diagram) on the original compressor. So, you need to have an unloader line run from the check valve to the unloader valve on your compressor pressure switch. That should resolve the issue as you have described it.
Thanks Willy. #4 in that diagram is the exhaust tube from the pump to the tank (via the check valve #6). It heats up a lot when the tank is filled.
The check valve has a 1/8 inch port on it but it is plugged (and it is seized). I can’t tell if that plug is original or not, and I don’t see any connection from the exhaust tube or check valve to the pressure switch.
I can try installing a new pressure switch that has an unloader valve (and the associated line over to the check valve, and a new check valve and 1/8 port).
As an alternate thesis… do you think it could be the case that the starting capacitor is not being engaged? Aren’t these driven by a mechanical centrifugal switch inside the motor? If so I could imagine that a 23 year old switch may not be working properly, or perhaps the contacts need to be cleaned.
Update: Hmm. searching the part number for the original pressure switch, I found this images.
https://images.app.goo.gl/nTtGcwM6yuic4w9SA
There is definitely an unloader tube, and my unit does not have one. I can add one, but I’m still not sure how it will help, as even when I temporarily disconnect the fill tube to ensure it is empty, the motor still can’t get started if there is pressure in the tank.
Tim, you’re guess is as good as mine, as you have the compressor right in front of you. My thoughts are that your compressor needs to unload the air over the piston when it stops, to ease the restart load. If that’s not happening, and there is no way for that air to vent out elsewhere, the additional load is enough to stall the motor on restart with air pressure in the tank.
On the other hand, in your follow up post which I’ve added to your earlier one, if there is no air in the tank, and that is the same as having the pump to tank tube unfastened, and the compressor will not start, sure check the start capacitor. Or, if there is air in the tank, and you disconnect the tank fill tube, then that removes the start load on the piston, and the compressor won’t start, check the cap.
You might want to remove the motor end cover and ensure that if there is a centrifugal switch, that it’s able to shift through centrifugal force.
I think it’s the motor. I have fully disassembled and reassembled everything. I have tried a new check valve, plumbed a new unloader line and new pressure switch. I believe the centrifugal switch is ok (I can’t directly check the centrifugal switch — I can’t spin the shaft fast enough by hand to trigger it. However, the switch does seem to operate smoothly, and while the motor tries to spin when powered on, the motor does not try to spin if the start capacitor is disconnected — I think that means that the centrifugal switch is closing properly). The motor/pump turn fairly easily by hand. However, when powered the motor only turns slowly and only occassionally does it get up to speed within a few seconds. If not up to speed within a few seconds, it blows the breaker.
So assuming it is the motor, I was thinking about looking for a used motor to try, if I can find one. The problem is that I don’t know the exact motor specs as it is only marked “3.5HP 11 gallon”. It does read “8.1@40 PSI 6.1@90” elsewhere. I imagine that these ratings may be overstated.
I did try to figure out the motor RPM. The motor has 24 separate channels in it that wires pass through. I think that means that it is (likely) a 4 pole motor with 1750 RPM (could also be a 6 pole motor with 1200RPM).
The piston on this thing seems huge to me. I estimate that it is a 3 inch diameter with a 1.5 inch plunge. That would put the piston volume at 10.6 cubic inches (3.14*(1.5*1.5)*1.5). If the RPM is 1725, then the no load CFM would be 10.6 (10.6*1725/(12*12*12)) which seems possible to me. (If the RPM was 1200, then the cfm would be 7.4). Regarding power, I would think that the largest motor that can actually be powered from 115V is 2HP (not 3.5). That would draw about 15 Amps. SO… I guess I will look for a 2HP 1750 RPM single phase 120V motor.
Tim, thanks for the update. If you have a motor rebuilder anywhere near you they can help you with the RPM of the old, and possibly help you with a used motor. Good luck.
So I couldn’t fix the motor.
The pump was integrated – it shared some of the motor housing. I cut the stator to separate the pump and motor components, and then mounted a second hand motor to the pump using a belt drive. It was pretty noisy and rickety (I had to grind the leftover part of the pump shaft to 5/8 and I didn’t get it quite centered).
I then picked up a decent two cylinder pump at princess auto for $129 CAD. With the second hand motor, I’m getting about 5.0CFM from it at 90psi. While it’s not exactly pretty, it works beautifully (the yellow hose is the discharge tube — i plan to replace that with a shorter one).
Someone far smarter than me said “necessity is the mother of invention”. Congrats on “inventing” your own solution. Well done.
I have a Campbell Hausfeld Air Compressor model fl3201 and I cannot find any specifications on the motor. And when I say I can’t find any specifications they have been spray-painted over and I can’t read them any help would be greatly appreciated
We are having trouble with the compressor cuting off and not having enough pressure. The switch was replaced on it and it’s still doing the same thing. When the air is used the compressor won’t kick back on.
Melissa, if the compressor was working properly before, in the same location and with the same power supply, the symptom typically points to a couple of things. One of them may have been the unloader valve failing, yet you’ve addressed this with a new switch which, I expect, also had a new unloader valve?
When you say that the compressor is cutting off without having “enough pressure”, does that mean that the tank gauge is registering a pressure that is lower than the normal cut out pressure and the compressor is stopping before it should.
That being the case you need to look at the start / run or run capacitor. Since I don’t know the model I can’t check.
If you look at the general troubleshooting page and scroll down you’ll find pages about this issue and what to do about it. Good luck, and let us know how it turns out, if you would.
I need replacement parts for this AIR Compressor , air hose, washers, Plastic fan , Model No. WL6600900Aj (AGMo1) 26 Gallon/ 1.7 HP. Pump No. WL390100AJ
Serial No.L6/22/2005. Can you Please help me. Thank You..
I have a Campbell hausfeld iron force. 22 gallon belt driven. It keeps getting hot and shutting off.
Chris, are you running it longer than normal? What’s the air tool you are using? Do you know the CFM requirements of the air tool. What is the HP of the motor? Did you change anything about the location where you are using it?
Only running about 15 minutes then it shuts off for 30-60. 5.5 hp. Using a gravity fed paint gun.
Check the motor capacitors. This page may help!
I have an old Campbell Hausfield 20-gallon air compressor that has started blowing a lot of oil out of the oil filler cap. I’m wondering if this is an indicator of piston ring failure/wear, and if so, can you give me a general idea of how difficult it is to replace the rings? It’s been a reliable compressor since I bought it in the late 90s but if it’s outlived its time, I don’t want to spend a lot of money or time trying to fix it. Thanks!
“piston ring failure/wear”, yes, I suspect that is the cause. If air and oil is blowing out the oil fill tube and cap, that air has to be coming from the compression chamber, and that means it’s blowing by the piston seals. No, I cannot comment on how hard this is, as I don’t know your skill set. Some folks will find this intimidating, others will find tearing down a compressor pump and rebuilding it a piece of cake. If you aren’t really handy with rebuilding stuff, this task may be beyond your skills.
Hello, I have a Campbell Hausfeld 6 hp 60 gallon 125 max psi compressor. I replaced the pressure switch with unloader valve and replaced the check valve in the top of the air tank. The problem I am having is that the compressor doesn’t turn off when I switch it to off. and when i do switch it to off the air comes out of the unloader fitting on the new pressure switch. This problem has been boggling my mind since all the parts have been replaced and I cannot locate a local business that repairs air compressors. Any help would help.
When you write “he compressor doesn’t turn off when I switch it to off”, what are you turning off, a lever or knob on the pressure switch, or a separate ON/OFF switch? If it’s a lever or knob on the pressure switch, and turning the switch to off doesn’t cut power to the motor, then the switch is likely wired incorrectly.
“When i do switch it to off the air comes out of the unloader fitting on the new pressure switch” – that’s supposed to happen, yet air should just bleed for a moment to clear the air over the piston. When the air continues to come out, that is indicating that the tank check valve is not keeping the air in the tank. Sorry, but if you’ve replaced it, the tank check valve is still suspect.
My compressor bill up pressure to around 120psi but will not shut off. It’s a Chamberlain Hausfeld 200psl, can you help?
Hi Jerry. I think you might mean a Campbell Hausfeld air compressor. OK, if the compressor is rated to cut out at 200 PSI, and the tank pressure gets to 120 PSI, goes no higher, and the compressor continues to run, then it’s quite likely it’s a pump issue. Maybe you could have a look at this page: https://fix-my-compressor.com/when-an-air-compressor-runs-and-runs/ and check out yours based on what’s listed here? Let us know what you find if you will.
I have a Campbell Hausfeld 13gal WL650000AJ. It wasn’t holding pressure so I purchased the head repair kit and new piston ring. All works very well now.
However, when I start the motor, the check valve at the tank blows a lot of air while filling. When it reaches 125psi it cuts off and there are no leaks, so the check valve appears to be working.
I never paid attention to that before, but thought if all that air wasn’t being blown out of the check valve, the tank would fill quicker. Is this normal?
Good that you were able to repair the pump. A pump kit works wonders on older compressors. I looked for images of your compressor, found some, and though difficult, did manage to see where the line from the pump enters the tank, that through the tank check valve. What I don’t see is where, at that point, there should be any leak? Some lower end compressors have a pin hole in a fitting or in the line to the tank which does bleed air while the compressor is running, and then, when the compressor stops, air bleeds off from over the piston through that hole. If the tank check valve works, no air should leak while the compressor is stopped.
Your compressor has an unloader valve, however, which is supposed to open when the compressor stops to dump the air, and it should not, as far as I can see, be leaking air while the compressor is running. You may need a new unloader valve, which are still available.
I have Campbell Hausfeld 21 Gallon tank air compressor will not build up pressure only up to 30 PSI, use to go up to 120 PSI.
One website said REED VALUE bad.
Shawn from campbells hausfeld said could be reed value or piston rings.
I sprayed WD40 on top piston did not leak for over two days . These is no model number on it shawn told me to send him pictures he’d try to match it with model no luck after week here are some pictures of the compressor. would like to fix it .
I’m not quite sure what your comment about spraying WD-40 on the piston means, James. Are you saying that after you sprayed the piston, the compressor would build pressure normally for two days? If not, what leak are you referring too. I’m not a Campbell Hausfeld person, and am not going to disagree with Shawn. I will say that the symptoms you refer to are commonly caused by a failing intake/pressure valve, a leaking piston seal that opens as the back pressure grows (though I would expect to feel air blowing out the oil fill tube vent if this were the case) or by a pump gasket that holds until the pressure reaches the 30 PSI, then opens, and air cycles back and forth between intake and pressure sides of the pump, and is not driven down into the tank. If you can get a pump repair kit that has valve plates, piston rings and new gaskets, that would, I expect, solve the problem.
I have a CH air compressor model # HU200001
I have to spin the fan to get the motor to run and then it does not build up any pressure in the tank…Any thoughts on what I need to do to fix it?
Sounds like a couple of issues, Jonathan. Make sure the plug is in a socket directly, not using any extension cord. If no difference on start, then it’s time to look at the capacitor connections on the compressor motor, and if they are good, then test the capacitor. See how on this site. As to no air going into the tank, three is a list of things to check on that page on this site. Please check them and let us know what you find.
I have a Campbell Hausfeld 15 gallon compressor model #HJ300101. It pumps up when turned on, but won’t restart after some air is used. I have to turn it off for a while & then back on. When turned back on, it pumps up fine. Shortly after motor turns off, I hear something click as if a switch is being turned off. Could this be the pressure switch or unloaded valve? Thanks for your help!
Test the compressor by letting all the air out of the tank, and then trying to start it. If it starts OK, test it again. If it works again, that suggests that the unloader valve is not functioning properly and it needs to be fixed.
Thanks for posting this information, and the Compressor will not build pressure page. I have an old CH WL6509 5.5 HP, 22 Gal. unit that was used to blow out my sprinkler system a few times years ago. It will not charge past 50 PSI or so, the compressor just runs and runs. Fortunately the tank holds pressure.
Hopefully I can find out what is wrong using the pages here and the documentation from the CH site.
Thanks again!
I have an older quad/60 gal. vertical tank. Model# CIQ71060V. As it starts, it does make a slight clicking sound. When it builds pressure to between 80psi and 90psi, it makes a grinding sound. This just started. If I let it cool down, it will start out the same way,l then at pressure it grinds again. I changed the oil, but that didn’t help. Any suggestions?
We think it may be a couple of issues on your Campbell Hausfeld compressor. We think the clicking may be related to a failing centrifugal starter on the motor. As to the grinding, changing the oil may have alleviated it a bit, but if it’s the crank bearing, which is our guess, it’s time for a pump rebuild.
Hi, My Campbell Hausfeld CI071080VMS air compressor was operating great until last week when a tube fitting crack Part#: TF060402AJ, I replaced it and since then i got a different problem. the compressor will start and built pressure at normal speed up to 150psi and it triggers the pop off valve Part#: V-215200AV and it keeps running( it should go up to 175 psi) and it will pop the breaker.
Is my Pressure Switch-135 Psi On/175 Psi Off Part #: CW207561AV Bad?
Thanks for your help.
We believe that your Campbell Hausfeld air compressor is popping the breaker as the motor is getting too hot from running too long. We also think that you may have somehow contaminated the PRV V-215200AV and it is releasing too soon, the pressure cannot build to cut out, and your compressor motor overheats. We don’t think it’s a pressure switch issue. The part V-215200AV is supposed to crack open at 200 PSI. Try pulling the plug, emptying all the air from the tank, removing the PRV and rinsing it in paint thinner. Let it dry thoroughly. Reinstall and start the compressor. Let it run up to normal cut out and stop. If the PRV doesn’t let go then cleaning it helped, but now you should prove that it will release at the design limit of 200 PSI. That becomes a problem as your pressure switch should turn off the compressor at 175 PSI or so. You can take a chance on assuming the PRV will crack at the 200 PSI, but without checking it, it may be safer to just replace it with a new one.
I just replaced the pump on my CH compressor. The old pump had an unloader valve. The new pump has a plug where the unloader line would go. It seems to operate fine, with no undue stress when it restarts. Are there pumps that do not need the unloader/ Should I remove the plug and connect it any way?.
A bit hard to be definite when we don’t know the model of the Campbell Hausfeld air compressor you have. If it is a fractional HP model, it is possible that the compressor does not require an unloader, or the unloader is a small hole in the top of the cylinder housing. If the pump had and unloader plumbed over to the pressure switch on the old model, then we would plumb the new similarly.